Hi Bruce,
When you first described the problem with your lens, you gave the impression that you were getting a generally soft image. Had it simply been a back focusing problem, I would have expected you to talk of a shifting of the field of focus and not a general softness. General softness seemed to me to suggest a problem with your use of VR, which is why I brought the matter up.
Nikon held the original patterns for VR, but chose not to use it at the time. When they finally did incorporate it into their lenses, the spin up time was over one second which, if you think about it, made the idea rather pointless in many circumstances. The current generation of Nikon lenses spin up in half a second, so even now you shouldn’t expect that you can instantly fire off the shutter and get good use from it. Both Nikon and Canon cameras are designed to isolate their lenses from vibrations from one to twenty HZ, and this impacts VR’s effectiveness at higher shutter speeds, as discussed by Thom Hogan in the article I previously mentioned. Thom is a consultant to Nikon and headed the team that designed the first digital camera many years ago.
There are some reviews specifically about your lens that might interest you. One discusses the use of VR and demonstrates how you need to allow it to spin up fully before it becomes effective, and the other compares its sharpness with the three available Nikon teleconverters. You might also note that there is a penalty for having VR on at all, which isn’t that surprising really, since it introduces a vibration all of its own. But I doubt that you will get too see this, unless printing images in A2 size.
One last thing, the lens is capable of sensing whether it's on a tripod, panning etc. as you would expect from such a costly piece of gear.
Good luck with it!
https://photographylife.com/reviews/nikon-300mm-f2-8g-vr-ii https://photographylife.com/proof-that-vibration-reduction-should-first-be-stabilized